Psalm's workflow uses custom code to merge duplicate contacts based on phone number. The action logs say 'Contacts merged!', but the contacts remain separate duplicates.

Justin points out the provided custom code uses an outdated V1 merge API endpoint (`/contacts/v1/contact/merge-vids/{idToMerge}`). He provides a link to the current V3 merge API documentation (`/crm/v3/objects/contacts/merge`) which the developer should use to update the code. Psalm later confirms updating the code based on this documentation resolved the issue.